What is the volume of a cylinder with base radius $2$ and height $7$ ? $2$ $7$
Answer: The area of the base is simply the area of a circle: $\pi r^2 = \pi \cdot 2^2 = 4 \pi$ The volume of the cylinder is the area of the base times the height: $B \cdot h = 4\pi \cdot 7 = 28\pi$.